Sorry for the slow reply mate. I don’t get to visit the forum as much as I would like. Time restraints. I posted a link to my Slic3r config file (the one I use for N-vent) in reply to your post on the youTube vid.
Here is the same link. https://drive.google.com/file/d/0B2nobe1HZXsEN3dWdWZOV2prWDQ/view?usp=sharing
I use very similar settings to my Tech-G (PETG) config. I set the Z height a little higher (prints are impossible to remove from the build tac otherwise) and reduce the retraction settings slightly (ooze/blobs are not really an issue with N-Vent even with a 0.4mm nozzle) I also print at the upper range of the recommended temp settings (255deg C) Print bed is set to 70deg C, higher than the recomeneded but I found this prevented any minor warping on large flat prints (the solder-less stepper mounts wanted to curl slightly due to the upper layers cooling too rapidly).
I print very slow (my printer requires this for decent quality) and I think it helps with N-Vent in particular for that very clean/smooth finish.
If you can share some pics of your results, I’m sure myself or some other of the more experienced 3d printers out there will offer some sage like advise.
All I can say is settings. I printed maybe 25-30 test cubes with very minor adjustments made to slic3r settings each time. To compare the first one printed in N-vent to the last one, is like comparing chalk to cheese.
I do this with every new filament I buy. I am still fine tuning the Polymaker PC Plus I have on hand. It is proving the most challenging material I have printed to date. Warping is horrible, like ABS but different. It refuses to stick to anything but build tac, but removing even the smallest part is next to impossible, plus everything must be printed on a raft (a bit like nylon). Its a pity because it has a lot of excellent properties. The strength and rigidity is insane!! This is one material where a heated build chamber would be awesome.